NEW YORK (REUTERS).- As a pop art pioneer, Andy Warhol blazed his way to fame with trademark Brillo soap pad boxes and silk-screens of Campbell's Soup cans.

But a new museum exhibit shows pop art was just a seven-year phase for Warhol in the 1960s, before his 1980s plunge into abstract art and Christian imagery, particularly his versions of "The Last Supper."

Flippant, brazen and flamboyant as an art world personality, Warhol long kept private his devout, lifelong Catholicism.

"Only his closest confidants knew he was a religious person and frequently went to Mass," said Sharon Matt Atkins, coordinating curator of the Brooklyn Museum exhibit "Andy Warhol: The Last Decade," which opens on June 18.

Little known is that Warhol attended church in the plush, Upper East Side of Manhattan, a world away from his famed downtown Factory studio complex, frequented by the eccentric and outlandish,

In his middle age, he began exploring religious themes in his art.

"After Warhol turned 50, he began a reassessment of his career," Atkins said. "We also start to see Warhol reflecting on the inevitability of his own death."

In the year before he died -- at age 58 in 1987 -- Warhol created more than 100 works that were offshoots of Leonardo da Vinci's "The Last Supper" fresco in Milan.

"For an artist obsessed with death ... the Lord's final repast functioned as the consummate disaster painting," Joseph Ketner said in the exhibition catalog,

"The image of Christ and disciples obsessed him," added Ketner, who curated the show for the Milwaukee Art Museum, where the exhibition was first on view.

Three of the show's Last Supper works are monumental, ranging between 25 feet to 35 feet in length, one of which is bathed in canary yellow.

Another piece juxtaposes a quartet of Christs with a trio of motorcycles, a swooping red eagle and a $6.99 price tag, emblematic of Warhol's outward irreverence but also revealing of his inner spirituality, according to Atkins.

The largest canvas has 112 portraits of Christ, recalling repeated icons in Byzantine art, said Atkins.

Warhol's parents, immigrants from Slovakia, raised him as a Byzantine Catholic, a denomination which had a church in the artist's native Pittsburgh.

Warhol's turning to abstract art, also after age 50, dominates the exhibition's first section. The influence of Jackson Pollock's jumbled drip paintings is clear in Warhol's series "Yarn."

Like a cat's cradle, it features intertwined hoops and loops, in a scramble of colors such as lemon-yellow, asparagus-green and coral pink.

The Brooklyn Museum exhibition includes videos from Warhol's TV series including his MTV program "Andy Warhol's Fifteen Minutes," Atkins said. Warhol predicted in the 1960s that in the future everyone will be famous for 15 minutes.

But the show's program excerpt lasts only 15 seconds.

(Reporting by Walker Simon; Editing by Patricia Reaney)